Method of preparing rayon tying twine



United States Patent 3 287 894 METHOD OF PREPARING RAYON TYING TWINERichard MacHenry, Prospect Park, Pa., assignor to FMC Corporation,Philadelphia, Pa., a corporation of Delaware No Drawing. Filed June 25,1964, Ser. No. 378,063 4 Claims. (Cl. 57-164) This invention relates toa method of preparing rayon tying twine. More particularly, it relatesto a method of preparing rayon tying twine in a package.

The machine application and tying of twine such as found in tag machinesfor stringing price tags and labels, requires a twine which will notshell off of its cone or ravel, which will tie a suitable knot, andperform satisfactorily on the machine itself.

Rayon yarn would be desirable for use as a twine since it is relativelyinexpensive and strong. Rayon alone, even when the strands are twisted,has not been found suitable as a twine for machine operation. Severalfinishes and coatings have been applied without complete success.

It is an object of this invention to provide a method for thepreparation of a suitable tying twine package for machine applicationand tying.

This and other objects are met in accordance with this invention whereinthe method of preparing rayon tying twine comprises twisting rayon yarnfrom 2 to 6 turns per inch, treating said yarn with a homogeneousmixture of from 90 to 95%, based on the volume of the mixture, of a C Calkanol and an aqueous dispersion of polyvinyl acetate at a solidsconcentration of from about 25 to about 65%, preferably about 30 to 40%by weight, winding the wet yarn into a package, and drying the package.

The twisting of the yarn is necessary to obtain a rayon twine having areduced tendency to ravel. While 2 to 6 turns per inch are requiredabout 4 to turns per inch are preferred.

The alkanols for this invention are those which are miscible withaqueous mediums and include, e.g., methanol, ethanol, n-propanol,isopropanol, and t-butanol. Isopropanol is preferred based on expense.The alkanols, aside from being miscible with water, are substantiallynon-toxic, do not degrade or swell cellulose material and have asutficiently high vapor pressure to evaporate from the yarn in areasonably short time. The use of the alka- 1101 as the carrier isresponsible for producing a nonshelling, firm package as compared to oneproduced with a water diluted polyvinyl acetate emulsion.

Emulsions of polyvinyl acetate resins are generally supplied at a highsolids concentration and may be diluted with water to obtain the desiredconsistency. After diluting, the emulsion is mixed with the alkanol toobtain the prescribed composition.

Additive materials in small amounts may be added to the compositionincluding plasticizers, pigments, coalesc- 3,287,894 Patented Nov. 29,1966 "ice ing agents and surface modifying agents such as clays andwaxes.

The following example is set forth to demonstrate the method of thisinvention.

Example 4000 ccs. of a polyvinyl acetate emulsion supplied at a sol-idsconcentration of about 55% was mixed with 4000 ccs. of water and stirreduntil well distributed.

8000 ccs. of the diluted emulsion was added to 34 gallons of isopropanoland stirred to obtain a homogeneous mixture.

This mixture was applied to rayon yarn of 1780 denier having 4.5 turnsper inch and the excess mixture stripped off. The yarn was then conedWet and the cone permitted to dry.

This cone was a non-shelling, non-ravelling twine which formed asatisfactory knot on a tag machine. The finished rayon twine is strongerand less expensive than comparable cotton string.

Various changes and modifications may be made practicing the inventionwithout departing from the spirit and scope thereof and, therefore, theinvention is not to be limited except as defined in the appended claims.

I claim:

1. A method of preparing rayon tying twine which comprises twistingrayon yarn from 2 to 6 turns per inch, treating said yarn with ahomogeneous mixture of from 90 to 96%, based on the'volume of themixture of a C -C alkanol and an aqueous dispersion of polyvinyl acetateat a solids concentration of from 25 to based on the weight of thedispersion, winding the wet yarn into a package, and drying the package.

2. The method of claim 1 wherein the alkanol is isopropanol.

3. The method of claim 2 wherein the dispersion of polyvinyl acetate hasa solids concentration of 30 to 40%.

4. A method of preparing rayon tying twine which comprises twistingrayon yarn from 4 to 5 turns per inch, treating said yarn with ahomogeneous mixture of about 94%, based on the volume of the mixture, ofisopropanol and an aqueous dispersion of polyvinyl acetate at a solidsconcentration of from 30 to 40% based on the weight of the dispersion,winding the wet yarn to a package, and drying the package.

References Cited by the Examiner UNITED STATES PATENTS 2,775,860 1/1957Morrison 57-164 X 2,856,750 10/1958 Lewis 57-153 2,964,262 12/1960Lessig et al 57-164 X FRANK l. COHEN, Primary Examiner.

J. PETRAKES, Assistant Examiner.

1. A METHOD OF PREPARING RAYON TYING TWINE WHICH COMPRISES TWISTINGRAYON YARN FROM 2 TO 6 TURNS PER INCH, TREATING SAID YARN WITH AHOMOGENEOUS MIXTURE OF FROM 90 TO 96%, BASED ON THE VOLUME OF THEMIXTURE OF A C1-C4 ALKANOL AND AN AQUEOUS DISPERSION OF POLYVINYLACETATE AT A SOLIDS CONCENTRATION OF FROM 25 TO 65% BASED ON THE WEIGHTOF THE DISPERSION, WINDING THE WET YARN INTO A PACKAGE, AND DRYING THEPACKAGE.